big 3 upgrade on integra, fuse box?

Yes. ok. Yes.. It's not a dumb question, but like your first question, I have provided answers. Have another read. Or search.

Yes your comment is correct which is why I said GOOD ground. We have had some older cars where grounding remotely, i.e. driver kick panel, trunk (boot) area, didn't work because of lack of continuity from movement, corrosion etc. By good ground, with a fully charged battery, going to an existent mounting hole or bolt position with the bare metal* exposed you should be looking at 12.5 between that point and the battery +. If that's the case no ground(earth) return cable is required. *I once looked at a C type Mercedes returned from the body shop, it wouldn't start and they were blaming the alarm. What actually happened is that they replaced the area in the trunk (boot) where the battery was mounted. I bared the metal and replaced the M8 grounding bolt. Job done. I STILL can't see what on earth requires 200 amps. You are almost into military requirements! But they use APUs/generators. You are looking at about 85 amps draw to start your car then up to 80amps with EVERYTHING, heaters blowers, AC, rear defog, headlights, windows, wash/wipe, horns etc. Add the values of ALL your fuses in both boxes as used when the engine is running. Bet you don't get over 80 amps. Oh and the sheer fun NOT of running 0 gauge through your car.

Well I don't think Integras have charge lights, and I'm not sure where to find a "voltage-sensing" isolator. Well I'm running approx. 2000 RMS setup with other random electronics. Using a calculator it says that a 1500RMS setup will use 125A max by itself at 12v. So I don't see how 200A is that ridiculous? A lot of these big car audio setups require more amperage than it's base car functions do.

wth do you think the square red icon showing a battery on your instrument panel is? Where apart from some deserted airfield are you going to be able to use 1500Watts? Say goodbye to your eardrums and window glass as the fenders fall off of your car.

Frankly it would have been a lot simpler to power your audio gear off of a deep cycle and charge it every so often, don't even connect it!

So how do you know if you have an electrical fault? But if you don't think you have one and you see no advantage to my suggestion(s), get a voltage sensing battery isolator. They are known as "smart" battery isolators, sensing isolators, and even battery isolators (though the PAC200 seems to be a plain relay). Enjoy their hype! Thanks howie ll - you managed to get a design parameter. Well done! So it's page #3 and we know we are talking about a 2kW RMS system. That's a 200A design by my general rules (ie, divide by 10V). So at full power, say 200A plus recharge current plus current for the other "minor" electronics. Incidentally, your starter motor probably consumes about 150A if it's a reduction type; otherwise it's probably 250A or more. But that is on its own unfused cable from the battery +12V. I mention that in case you want to compare cable sizes.

Just realised what a PAC unit is. I've installed them, you only need a 1.5mm (about 16 gauge US) between the two. It's simply charging the second battery. Personally I'd use the cars original battery in the front the one shown in the rear.

My last post missed howie ll's 2 prior replies. I suspect our opposing electron spin causes delays.... Curse that Coriolis dude! Keep in mind that when the vehicle is charging and the amp is running, the interconnect will be trying to provide the amp/load current plus whatever has been discharged from the battery. FYI - My 38AH AGM has about 40A initial charge after cranking (140A for a few seconds) and drops to under 10A within one minute. (And hence why I use self-resetting circuit breakers between my batteries). PS - Am I correct - the PAC is simply a 200A continuous rated relay? (aka contactor etc.) I'd assume a 1A or higher solenoid current which may be too much for some alternators.

Wait, what? You're saying I should wire the 2 batteries together using 16 gauge wire? with that PAC relay, or am I reading that incorrectly? But yeah, the stock battery died a while ago and I replaced it with that yellowtop as seen. The auxiliary battery I'm going to use was already purchased anyway.